<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <!--引入外部样式表-->
    <link rel="stylesheet" href="./outer.css">
     <style>
     /*@import url声明，必须放在style的第一行*/
      /*  @import url(./outer.css);*/
    div{
        width:100px;
        height:100px;
    }
    </style>
</head>
<body>
    <div style="color: blueviolet;">块级元素</div>
</body>
</html>